1. Field of the Invention
The present invention relates to wireless power transmission indication. More specifically the present invention relates to wireless power transmission indication in wireless communication devices.
2. Background of the Invention
Cellular telephones are tremendously popular. It is estimated that at the end of 2007 the total worldwide subscriber rate reached 3.3 billion. Close to 80% of the world's population enjoys mobile telephone coverage, a figure that will only increase. As cellular telephones gain popularity, their functionality has increased also. Standard service includes voice calling, caller ID, call waiting, and voice mail. Service providers also offer text messaging, push mail, navigation, and even a high-speed internet connection directly to telephones. Cellular phones frequently have cameras, with the resolution capabilities increasing with each new model. These cameras allow users to take pictures and videos.
Most cellular telephone models have at least two indicators on them. One of these indicators displays the amount of battery life, while the other indicator displays the amount of signal strength the cellular telephone is currently receiving. The battery life indicator shows an estimate of the amount of energy the battery contains. The battery life indicator can be a little confusing though, because cellular telephones do not constantly use the same amount of power. In fact, the power consumption greatly increases during a voice transmission than when at rest. The signal strength indicator displays an estimate of the quality of the signal the cellular telephone is currently receiving.
The power consumption by a cellular telephone increases during a voice transmission because the Radio Frequency (RF) transceiver goes from a rest state to a high-powered transmission level. The power transmission level varies during a voice transmission depending on the distance of the cellular telephone from the nearest cellular tower and the amount of environmental noise in between. “Environmental noise” refers to interference by electromagnetic waves, electronic devices, buildings, walls, etc. The quality of the voice transmission is measured by the cellular tower as well as most cellular telephones.
At the beginning of a voice transmission, the power transmission level is usually high, if not the highest. This ensures that the voice transmission will be clear at the beginning. The cellular tower measures the quality of the voice transmission and determines whether or not the power transmission level is too high. Since the power transmission level starts very high, if not the highest, it can usually be lowered to some extent. If this is the case, the cellular tower sends a message to the cellular telephone to lower the power transmission level within a few seconds after the voice transmission is initiated. Because the environment is constantly changing, the quality of the voice transmission is constantly monitored. If at any point it is determined that the voice quality is too low, then the cellular tower sends a message to the cellular telephone to raise the power transmission level.
The power transmission level has a direct relationship with the power consumption of the cellular telephone. Currently, there are fifteen different power transmission levels that network operators use. Most cellular telephone manufacturers give approximate battery life in terms of standby time and talk time. The talk time is usually a measure of how long the battery lasts at the highest power transmission level. In reality, the power transmission level can be lower than the highest power transmission level. This makes it hard for users to estimate how much talk time they have left.
A higher power transmission level also creates more electromagnetic radiation. Many people feel that they should closely monitor the amount of electromagnetic radiation they receive, especially around their head. Although studies on electromagnetic radiation from cellular telephones have been inconclusive so far, radiation in general has been linked to cancer. It may be many years before we know for sure what the effects are, but in the meantime, some people prefer to avoid exposure to radiation as a precaution.
What is needed in the art is a cellular telephone that indicates the instant power transmission level. With this knowledge cellular telephone users can more accurately estimate how much battery they are actually using. Users with low battery can determine whether or not to take a call based on the power transmission level. Users also can avoid voice calls that insist on using a high power transmission level while favoring voice calls that can use a lower power transmission level.